钛合金内螺纹表面的冷挤压强化技术

Strengthening of Internal Threads in a Titanium Alloy by Cold Form Tapping

本文将切削—挤压复合攻丝新技术成功地用于钛合金内螺纹的加工.这种方法不仅可以减小挤压扭矩而且能够强化螺纹根部.经挤压强化的螺纹其疲劳寿命有显著地提高,这主要归因于挤压螺纹表面的残余压应力,高的位错密度和低的粗糙度.

In this paper, a new thread tapping method, called combined cut and form tapping, was successfully used for producing threads in a titanium alloy, which may not only reduce forming torque but also strengthen the thread root where initial fatigue cracks very often occur. The fatigue lives of strengthened thread can be enhanced significantly by the method, because of the high compressive residual stress, the increase in dislocation density and the decrease in surface roughness.